Justin Bieber and Hailey Baldwin kiss in New York

Justin Bieber and Hailey Baldwin showed the world they are back together as they were spotted kissing in New York.

Justin Bieber and Hailey Baldwin proved they were back together as they were spotted kissing in New York.

Justin Bieber and Hailey Baldwin

The on again off again couple were seen making sundaes in Sag Harbour over the weekend, and locked in a "passionate make-out session", the New York Post's Page Six column reports.

The sighting comes after a source revealed Justin and Hailey have been "casually dating" and things have been "heating up" between them.

The insider said: "Justin and Hailey have always been into one another. They dated in 2016 briefly, and the feelings never really went away. Justin and Hailey have been casually dating for roughly a month, but things seem to be heating up as the two are spending more and more time together."

Last month, Hailey admitted she has "moved past" the "weirdness" of her split from Justin.

She explained: "Justin and I were friends for a long time. I met him when I was really young and he was one of my best friends. Everybody knows that at a certain point in time that turned into something else, but that just happens when you're 18, 19. It was what it was. We went through a long period of time when we weren't friends. We didn't speak for quite some time and there was a lot of weirdness that went on. We've moved past that. I'd never been through [a high-profile relationship] like that. But it brought both of us to the realisation that we just work much better as friends. He's somebody I really cherish. Now it's a very mature situation. It's good."